Stepping switch



Oct. 8, 1963 J. M. LORD ETAL STEPPING SWITCH Filed Oct. 11, 1961 FIG. 1

IN V EN TORS- JOHN M. LORD JAMES .KOPPENSTEINEF United States Patent 3,106,626 STEPPIN G SWITCH John M. Lord, Oak Park, and James V. Koppensteiner,

Chicago, 111., assignors to Automatic Electric Laboratories, Inc, Northlake, 111., a corporation of Delaware Filed Oct. 11, 1961, Ser. No. 144,461) 1 Claim. (Cl. 200-105) This invention relates to switches, and more particularly to electromagnetic stepping switches.

Heretofore, stepping switches were designed so that an electrically conducting wiper moved in step by step fashion across a row of fixed bank contacts. These prior art switches thus were inherently limited to a make contact type of operation. However, there are also applications in which it is necessary to effect switching operations other than those that can be brought about by letting a contact wiper sweep over a row of fixed bank contacts. For example, it may be desirable to use the switch for interrupting one or more circuits. The invention accordingly provides a switch with a bank assembly having a plurality of contacts at least one of which comprises a pair of contact elements having a first position and a second position, the position of the last mentioned contact being controlled by a switch wiper.

The switch shown hereinafter, by way of example, employs bank contacts which are normally closed, in conjunction with a wiper of electrically insulating material which serves to separate these normally closed contacts as it is stepped around the bank. This level of normally closed contacts may be interspersed with levels of conventional contacts and corresponding conventional wipers. The mounting for the aforementioned special Wiper is designed so that the wiper may be easily placed at any level of the stepping switch.

More particularly, the embodiment of the invention disclosed herein comprises a stepping switch having break contacts at the top level of the switch with a Wiper of insulating material provided at the corresponding level of the wiper shaft. The wiper is molded of one piece plastic material having electrical insulating properties and having a generally knife shaped contour. Each normally closed contact is made of a pair of make contacts on opposite sides of a conventional arcuate spacer of insulating material by forming the outer ends of these contacts so that they normally touch. All other con tacts and wipers of the stepping switch are of the type commonly used in telephone systems.

The invention will be more fully understood from the following detailed description of an embodiment thereof. In the accompanying drawings:

FIG. 1 is a top view of the hub which carries the knife shaped wipers. In this view, one wiper has been removed to show the mounting arm.

FIG. 2 is a top view of a stepping switch showing, in addition to the conventional elements of the switch, a knife shaped wiper and its associated break contacts in the top level of the switch. Also shown is the stepping mechanism.

FIG. 3 is a perspective view of a knife shaped wiper showing the shape of the blade, and the recessed portion thereof which receives the mounting arm.

FIG. 4 is an enlarged perspective view of a pair of break contacts.

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FIG. 5 is taken along line 55 of H6. 2, showing the bank contacts, wipers, and wiper shaft.

Referring now to the drawings, in FIGS. 2 and 5 a rotary switch 21) is shown having bank assembly 107 and wiper shaft 106 mounted on frame 126. In its general construction this switch may be similar, for example, to that shown in U.S. Patent 2,710,896 to K. W. Graybill et al. Shaft 1136 may be rotated in a stepwise manner upon intermittent actuation of coil 1G9. When actuated, coil 1119 attracts pivot arm 112, which pulls pawl 1.11? over ratchet wheel 115, and when coil 109 is released, pawl 116 is urged against wheel by spring 12%, rotating shaft 1116 one step. Detent 127 engages the teeth of wheel 1 15 and prevents rotation of wheel 115 in the reverse direction. In FIG. 5 it is observed that shaft 1% serves as a mounting for conventional wipers 11 i and special :wiper '1111, while bank assembly 197 mounts both the conventional contacts 113 and the special contact elements 103 and 104. Insulator 128, which is similar to the insulators 121) and 121 of the remaining levels, separattes contacts 11% and 1114 in bank 1-07, however the outer ends of the contacts 1113 and 1114 which are otherwise similar to contacts 103, are for-med as shown in FIG. 4 so that they normally touch, thus producing a break contact 21.

Knife shaped wipers 1131 are made of electrically insulating material and are shown in FIGS. 1, 2, and 5 as being mounted on huh 1411, which, in turn is placed on shaft 1% in alignment with a corresponding row of break contacts 21. GE course, insulators 116, 117, 118, and 119 of wiper shaft 106, and insulators 121), 121, 128, and 12@ of bank assembly 1&7 need be of the proper thickness to facilitate alignment of wiper 100 with its respective row of break contacts 21. It is noted that break contacts 21 and wiper 101 may be placed at any level or levels of switch 20. In this manner, it is possible to have all levels of a particular stepping switch equipped with break contacts, or to have any combination of bank contacts and conventional contacts. For example, the special contact levels may be intermixed with the conventional contact levels if required.

As shown in FIG. 3, each wiper 1th) has a thin leading edge 124 and a thick trailing edge 125. Leading edge 124 is at an angle with respect to trailing edge 125 such that the outermost end of the leading edge 124 is the first portion of wiper 1110 to enter break contacts 21. Furthermore, each wiper 1th) is hrictionally held on an arm 1112 of hub 10 1 by means of circular staking 122 on the sides of arm 1112. This staking 122 protrudes into the sides of recess in wiper 100 and securely holds wiper 101) to arm 1 32.

While we have described the above principles of our invention in connection with a specific embodiment, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope and spirit of our invention as hereinafter claimed. It will be understood that the invention can also be applied to switches other than those shown, for example, to two motion stepping switches.

What is claimed is:

An electromagnetic stepping switch comprising: a frame; a shaft carried by said frame and mounted for rotary stepwise movement; a stepping mechanism mounted to said frame for rotating said shaft; 9. bank 3 assembly including one or more arcuate rows of normally open contacts disposed concentrically about said shaft and \angnlarly spaced apart rows corresponding to the steps of said shaft, and one or more arcuate rows or pairs of normally closed contacts spaced concentrioal-ly about said shaft; at least one substantially flat wiper carried by said shaft for contacting said normally open contacts, and at least one second Wiper for opening said normally closed contacts comprising a hub portion secured to said shaft, an arm radially extending from said hub, and a blade portion fixed to said arm and made of insulating material, said blade member including a relatively thin edge for entering between said normally closed contacts which tapers back to a relatively thick A. trailing edge, said trailing edge being relatively thin at said fixed end and relatively thick at the free end thereof thereby providing minimum surface engagement between said normally closed contacts and said blade member.

References Cited in the file of this patent UNITED STATES PATENTS 1,273,245 Lundell July 23, 1918 2,083,722 La Via June 15, 1937 2,578,940 Morris Dec. 18, 1951 2,710,896 Graybil l et a1. June 14, 1955 2,760,018 Spenard Aug. 211, 1956 2,786,103 Bevins Mar. 19, 1957 

